Hydraulic cements and method of making



Patented Feb. 20, 1951' EXAM awn v Schenker HYDRAULIC CEMENTS AND METHOD OF MAKING Fritz A. Schenker and Aiphons Ammann, Zurich, Switzerland, assignors to Kaspar Winkler & Zurich-Altstetten, Switzerland, a copartnership consisting of Kaspar Winkler and Fritz A.

No Drawing. Application December 13, 1946, Se-

rial No. 716,172. In Switzerland December 29,

" This invention relates to new and improved concrete, mortars and the like. More particularly, it relates to concrete or mortar which, in

. "frost and to the agents which, when incorporated in the cement or mortar, impart the improved frost-resisting properties to such concrete or mortar.

.:United States Patent 2,174,051 discloses the incorporation of agents to concrete or mortar whereby the fluidity of the cement particles (suspensoids) is increased and the water-come I u agen'tsf'termed fluidity-increasing agents,"

are nonipamers, KW,-

and also do not reduce the surface tension of the water added to the cement mix. However, such "I fluidity-increasing agents do not improve the frost-resisting properties of the cement because they do not increase, but rather decrease, the

4 peculiarity of cement to produce bleeding. Due

1 tobleeding, channels similar to those formed by U suction and which produce undesirable effects in.

regard to frost-resistance are obtained. The formation of channels offsets the improvements which are obtained due to the increase in fluidity or the cement particles and reduced water-cement ratio. V v

. Frost-resisting properties of concrete and cement have been improved when 'gas-entraining agents-are incorporated in concre or mo ar.

uc gas-entraining agents, during the period of mixing, produce a large quantity of small air pores which are entrained in the concrete or mortar; In spite of the ct that t por may beconnecte esr'cano' pa y However, the improvement in frost-resistance by the use of gas-en training agents is only obtained by sacrificing other important and desirable'properties of the concrete- By entraining air in concrete or mortar, the specific gravity, compressive and fiexural strength, the adhesion to steel, and the adhesive strength toward concrete are considerablyreduced, whereby the general use 01 its hardened form, has improved resistance to 14 Claims. (Cl. 108-88) resisting concrete is either restricted or requires special precautions.

An object of this invention is to provide concrete, mortars, etc. containing hydraulic binding agents and which in their hardened form have improved frost-resistance.

Another object of this invention is to provide an addition which, when incorporated in concrete or cement, will produce a product having improved frost-resistance properties without sacrificing other desirable properties.

Other and additional objects will become apparent hereinafter.

The objects of the invention are accomplished, in general, by incorporating both a fluidity-increasing agent and a gas-entraining agent in concrete or mortars containing a hydraulic bindin aent.

The a ents can be added simultaneously, as in a mix ure,: o separa r I' manufacture of'tHe'EEliiEfitfGtYift r' hfidmis of ey 'are added during the pBiiiited in the cement-during or after the manu-' facture thereof and the other incorporated .in the concrete or mortar during the preparation thereof. Thus, for example, the gas-entraining agent can be added to the clinkers or to the cement, and thefiuidit'y-increasing agent subsequently added, as, for instance, at the building site when the concreteor mortar is produced. j

Any d aslnsia eptxpr g gtur such fiuidit ihcreasing agents can be used. In

general, and as referred to in the claims, by fluidity-increasing agent is meant a compound that reduces the volume of the paste in concrete without reducing the surface tension of the water, whereby when water is added to a cement, mortar or concrete containing such agent the fluidity of are in the form of extremely fine powders. Calthe cement particles is increased but the harshcium, magnesium or aluminum or their alloys are ness of the mix is not improved. flm'guty-inmustrmples of metals which, met creasin agents, such as non-gaming organic with cement, produce hydrogen.

hydro .ed ca'rboxylic ac compound con- 5 If desired, mixtures of agentragigg agente, ti in the nucleus and such as mixtures o f air-ent raining agentsf'a mixture of gas-f fits, or of ritTaininfgent and a gas-forming agent can be used. tetrah drox adi In general, to obtain frost-resistant concrete, saIE and derivat as ificlosed E United the volume of air or gas entrained in the cement States Patent 2,174,051; compounds of the nature is from 3% to 8% per vom above t t of ami o acids that con 111 more than one carmally entrained in cement. ThLgas-entrginigg 1 'ou na a sition an have thegenagent, i. e. air-entraining agent or gas-forming e arm a o 2 0 )3 wherein R is metal, is utilized in small amounts and dependany adicaior gr ou 1 a cast 2, such as, ing on its efllciency can range from 0.005% to fo'f e xafiffiefnitrilo-triacetic acid, ethylene-di- 0.5% of the weight of the hydraulic binding amino-tetra-acetic acid, mic difietic acid, agent. The fluiglity igqg ggfi figfi is utilized meihfi ammo 10 aM malso in small amounts. Usually, the quantity of diacetic aci uram 'I- acetic aid, or ho go the fluidity-increasing agent is from 0.02% to id, etc. are illustrative ex 0.5% of the weight of the hydraulic binding agent. amples of fluidity-increasing agents. The results obtained by this invention are in- The gas-entraining agent can be either an airdeed surprising and unexpected. According to entrairmfimrming a ent. In gen- United States Patent 2,174,051, the addition of a marred T3 in Efie MERE 3 5$? air-enfluidity-increasing agent, such as an 0 acid, to training agent" is intended any surface-active concrefi or mortaf produces an increase the agent which reduces the surface tension of waEr specific weight and the oxy acid increases the E al'fafifie solution wHicH E solu5le m alEline surface tension of the water whereby the producsolutions and which forms a large quantity of tion of foam is inhibited. It was therefore to be small as pores in alkaline solutions by foamln 3o expected that when a combination of a fluidityactimby as releas' cn i i ticfiwi mm s eaaseatu as an g g mam atria? chum Art ci 1 or natural air ntra in ingagent were addedftfie fam-proz ,r-fi resins which are insoluble ne'fitfal or acid ducing properties of the air-entraining agent and am used. Fir or plfie tree resifis i'rlsoIuBle m be influenced unfavorably. Surprisingly, however, the air content of 1 :4 mortar for instance, in um, o a an e e are us ra we'ex which both an air-entraining agent and afluidityp as 0 na ural resins which can be used. The increasing agent were incorporated, showed no fir or pine tree resins, commercially sold under unfavorable effect of the pore formation. On the the trade-name M; can be obtained by the 0 contrary and most amazing, an increase in foamprocess disclosed in United States Patent forming characteristics was obtained, as shown 2,193,026. Equally satisfactory are the resinates, by the following Table I:

Table I Oommbined taddltion I or per can based on mutant ncrease Air content mt I of mortar m; addition tuna conin per cent of mom mmmned tent without the qusntit calcium salt y by volume in in per cent cemsn of volume of dextro ,5- Odd.

D1 9. 0 0. 01 10. 2 18. 3 0. 02 I. 4 0. 02 15. 5 14- U 0. 0: l7 6 0. 03 19. 7 11. 9 0. o 21. 0 O. M 2L 8 3. 8

I The yum rcsinatc is vlnsowwutmlized with caustic particularly in the form of the alkaline salts. From Table I, it is apparent that to produce a 0 Very suitable also are we agen s, suc as W cement or concrete of a certain air content, the

a soluble alkali salts ofs 0 or s ates, such proportion of the ai r;e13t,rgi1. in -2 1; can be reas, for example, I5 Isfifiates or smonate's, sold duced approximately 10% when a fluidityinunder the trade-names "Igepone" E stmacreagggmflfient. such as the calcium saltof tea;-

1 ne, alkali-soluble synthetic resins such as adipic aci .15 mi. TEE aIsB causes 11 em u ormaldee on or a east considerable reduction of -Wm e ye, Q3. undesirable bleeding. 7

ormalsem 0 Ta 7 ac Hydraulic binding agents require water for are no s e ite 0 ac hardening. For the complete hydration of ortwetting agents becausethey form insoluble earth land cement, 12% to 15% water is required. alkali or aluminum salts and they are, therefore, ms water, whicfi 5 added when cement precipitated when they are mixed with mortar or or concrete is mixed, remains in the paste in g the form of fine capillaries or pores. For example, 1 cubic yard of concrete made with 5% bags of cement and having a water-cement ratio of 0.6, has a pore volume resulting from surplus K water but which are soluble in alEH solutions therefore the formation of closed air pores would water of approximately 3 cubic feet. The water thus obtained in the capillaries can, for instance. evaporate. The capillaries can, however, fill up with water immediately when they come in contact with it. These capillaries are of the greatest importance inregard to the behavior of cement against frost action. The great advantage caused by the addition of a fluidity-increasing agent is air and afterwards 14 days in water. Two of 'each of the respective 4 beams were then frozen and thawed 50 times, and the other two were stored in water. After the 50 cycles of freezing and thawing, all specimens were tested for flexural and compressive strengths. The results as well as additional information are given in Table II:

Table II without m After 50 cycles of freez- Reduction of strength Addition casing 890cm: ing and thawing caused by freezing Addition a; 3333i p r 2:113! m h rg Com Com m m content e ened g Flexural g Flexnral g Flexm'al mortar strength, strength strength, strength strength DJJ. p.s.i. pdi' p.s.i. P'LL' p.s.i.

2. 2, 865 708 2, 475 391 390 311 12 2. 15 2, 260 617 1, 620 278 640 339 14 2. l1 1, 705 5% 809 91 8% 431 9. 5 2. 21 3,565 863 2, 615 49! 950 $69 Tetrahydrcry adipic acid.... 0. 125 ll. 0 2. l8 2, 770 743 1, 463 254 l, 307 480 13. 0 2. 16 2, 530 517 981 1, 549 473 9. 2. 16 2, 585 613 2, 300 5% $5 7111801 resin 0. 025 11. 75 2. 10 2, 514 1, 835 344 325 dime 1125 11 o a' 14 21 e10 683 2' 595 625 15 5a 025 12.: 2. 0e 2, 115 594 2: 075 s79 40 15 p. s. i.-pounds per square inch. that the pore volume of the capillaries of the concrete or cement is reduced in accordance with a reduction of the water-cement ratio. The reduction of the pore volume, according to the example set forth in this paragraph, can be from V 0.35 to 0.55 cubic feet per cubic yard of concrete. In view of the fact that air-entrafmingagents produce a porous cement pastwhich porescaiinot be filled with water, the volume of air necessary to produce frost-resistance can be smaller when reducing the capillary pore volume. As proven by tests using combined additions of a fluidity-increasing agent and a gas-entraining agTfiEmtfUrr-of the water-cement ratio is possible togeth r as-entrainment. In this manner, mortar or cone can be produced which upon exposure shows an improvement against frost as well as improvements in other properties which cannot be obtained by adding the fluidity-increasing agent alone or adding the gas-entraifii'r'ig'figehf' alone.

/ Among the improved res'ults obtained by'the conjoint use of the fluidity-1n creasing agents and the gas-entraining agents are the following:

Reduction of water absorption; Impr frost and climatic influences;

Flexural and compressive strengths; Adhesinnlcpsteel and in cons to reduction or elimina ion of scum.

In order to show the results obtained by this invention, tests were carried out using comparative mortars: (a) mortars consisting of 1 part cement, 6 parts sand,with 12%, 13% and 14% gaging water respectively, and (b) mortars of the same composition but using additions with a reduction of the water-cement ratio to obtain the same workability, the uniformity of the workability being determined by measuring the spread r on a flow table according to Haegermann. Each mortar was mixed for 3 minutes and each mortar was formed into 4 beams, 4 x 4 x 16 cm. The additions, listed in percent of the quantity of cement, were added in the form of powder prior to the gaging of the mortar. After stripping, each specimen beam was stored for 14 days in moist As shown by Table II, the reduction in strength of the specimens without addition caused by frost is considerable, and the higher the water-cement ratio the greater the reduction. The addition of a fluidity-increasing agent alone resulted in higher strengths, but the reduction in strength caused by frost was greater although the final strength was as high as or higher than those of the specimens without addition. The addition of air-entraining agents alone produced a considerable improvement in the resistance to frost,

but the strengths were substantially lower than those of the specimens which contained no addition. The specimens containing both an airentraining agent and a fluidity-increasing agent showed a very pronounced improvement with respect to frost-resistance, so that these specimens can be considered to be substantially completely resistant to frost. In those specimens containing an air-entraining agent and a fluidity-increasing agent, a reduction in strength does not occur even with increased addition of water. This is in spite of the fact that in the tests, those specimens containing only one addition compound showed a considerable reduction in strength with increased addition of water. The improvements obtained by the conjoint use of both an air-entraining agent and a fluidity-increasing agent are indeed surprising, since the improvement in resistance to frost and in com- When both an air-entraining agent and a fluidity-increasing agent are used, the air-entraining agent reduces the increase in adhesive strength caused by the fluidity-increasing agent to a conitiii 'ployed with other materials which are added to concrete and mortar mixes, such as kiderably lesser degree than expected, as shown by the results set forth in the following table III:

Table III s cmc Compres- In Waterg ht Bond to Improve Bond in Improvesivc Improve- Additian cent of cement g steel ment Joints ment strength, mmt

cement ratio p. s. 1. per cent p. s. 1. per cent 7 days per cent concrete a L I g i t hout a i d ithgn 0.65 2. 43 672 244 2, 485 um trail acid "02002" 0.125 0.57 2.4.5 873 +30.0 389 +59-0 3,050 +23.0 C Sodium rosinate oi Vinsol resin 0. 02 0. 6.2 2. 27 362 46. 2 166 32. 0 l, 905 23. 5 Dairy! alcohol sulfate 0. 02 0. 69 2. 35 407 26. 0 102 58. 1 2, 130 1L 3 Q Aluminum in powder form 0. 03 0. 61 2. 35 487 --26. 0 111 -64. 7 2 N5 -11. 2

alcium salt of tetrahydroxy odipic 35 r E a in B' g: g 0. 64 2. 31 645 --3. 7 258 +6. 0 2, no lL 8 Calcium salt of tetrahydroxy adipic 3 0.65 2.40 14.5 +11.0 425 +7 ma) +w.o

8 0.51 2.44 m +1s.o 185 -24.4 2,170 +n.o

p.r.i.-poundsperequareineh.

In Table III, concrete of plastic consistency was made of 1 part cement, 2 parts sand and 5 parts of coarse aggregate. Such concrete was made without and with the various additions set forth in the table, the additions being added in dry form before or during The quantity of water added was measured so that a slump of 2 to 2 was obtained Cubes 4" x 4 x 4 were made with a smooth steel bar of 0.4" diameter and 5" in length embedded therein. After curing for 7 days, the adhesive strength of the steel to the concrete was determined by pulling out the steel bar.

As shown by Table III, when an air-entraining agent is used, the bond strength of the concrete to steel is materially reduced. However, by the conjoint use of the fluidity-increasing agent and the gas-entraining agent, the detrimental effect of the gas-entraining agent is overcome and con siderable improvement in bond strength obtained.

The formation of scum and laitance on the surface of the concrete, which is more or less pronounced depending upon the consistency, is very undesirable. These layers of scum, which are present partly as compact, shiny, and partly as loose layers, have insuillcient adhesion to the concrete. Air-entraining agents enhance the un? favorable conditions in construction joints. By the present invention, wherein gas-entraining agents and fluidity-increasing agents are con- Jointly used, the undesirable action of the airentraining agents and the desirable action of the fluidity-increasing agents are not additive, but the desirable action of the fluidity-increasing agents is more pronounced and prominent.

In order to determine the bond in joints, the lower half of an upright form for producing beams 5" x 5" x 12" was filled with concrete mixture used in the test set forth in Table III. After hardening for 3 days, the upper half of the form was filled with the same concrete, mixed at that time, and without changing the concrete on the surface of the old concrete. After 'the upper portion of the concrete was cured for 7 days, the samples were tested for flexural strength. The results obtained are listed in columns 7 and 8 of Table III, the flexural strengths listed giving measure of the quality of the concrete surface.

The conjoint use of the fluidity-increasing densifyins. water-repellent, dispersing or setting time-regulating compounds, etc.

Since it is obvious that various changes and modifications may be made in the above description without departing from the nature or spirit thereof, this invention is not restricted thereto except as set forth in he appended claims.

We claim:

l. A method of improving the frost-resistance of structures formed from concrete or mortar mixes having a hydraulic cement binding agent, which comprises incorporating a gas-entraining agent and a fluidity-increasing agent at any stage prior to the completion of the mixing of the components constituting the mix, the fluidity increasing agent being selected from the group consisting of tartaric acid, citric acid, saccharic acid, and tetrahydroxy adipic acid.

2. A method of improving the frost-resistance of structures formed of concrete or mortar mixes having a hydraulic cement binding agent, which comprises incorporating a gas-entraining agent and a fluidity-increasing agent in the hydraulic binding agent, and thereafter mixing such bydraulic binding agent with the other components of the mix, the fluidity increasing agent being selected from the group consisting of tartaric acid, citric acid, saccharic acid, and tetrahydroxy adipic acid.

3. A method of improving the frost-resistance of structures formed of concrete or mortar mixes having a hydraulic cement binding agent, which comprises incorporating a gas-entraining agent in the hydraulic binding agent, mixing said hydraulic binding agent with the other components of the mix, and prior to the completion of said co mixingincorporating a fluidity-increasing agent,

agent and the gas-entraining agent can be em- 5 5. A concrete or mortar containing a hydraulic 'auasu cement as the binding agent, an agent which increases the fluidity of the suspensoids, and a gasentraining agent, the presence of both the fluidity-increasing agent and the gas-entraining agent imparting frost-resisting properties to structures formed of said concrete or mortar, the fluidity increasing agent being selected from the group consisting of tartaric acid, citric acid, saccharic acid, and tetrahydroxy adipic acid.

6. A concrete or mortar as set forth in claim 5, wherein the gas-entraining agent is a substance which produces a gas when said concrete or mortar is mixed.

7. A concrete or mortar as set forth in claim 5, wherein the gas-entraining agent is an alkalisoluble resin.

8. A concrete or mortar as set forth in claim 5. wherein the gas-entraining agent is an alkali salt of a resin.

9. A concrete or mortar as set forth in claim 2 binding agent, the fluidity increasing agent being 'seiected from the group consisting of tartaric acid. citric acid, and saccharic acid, and tetrahydroxy adipic acid.

12. A concrete or mortar as set forth in claim 11, wherein the gas-entraining agent is an alkali soluble resin.

13. A concrete or mortar as set forth in claim 11, wherein the gas-entraining agent is an alkali salt of a resin.

14. A concrete or mortar as set forth in claim 11, wherein the gas-entraining agent is selected from the group consisting of the gasoline-insoluble resin obtained from pine and fir trees and the alkali salts thereof.

FRITZ A. SCHENKER.

ALPHONS AMMANN.

REFERENCES CITED The following references are of record in the o flle of this patent:

UNITED STATES PATENTS Number Name Date 528,995 Smith Nov. 13, 1894 2,174,051 Winkler Sept. 26, 1939 2,360,518 Scripture Oct. 17, 1944 2,478,831 MacPherson Aug. 9, 1949 FOREIGN PATENTS Number Country Date 379,320 Great Britain 1932 OTHER REFERENCES Barton, Air Entraining Cement Manufacture Rock Products for Nov. 1944, pgs. 39 and 112. 

1. A METHOD OF IMPROVING THE FROST-RESISTANCE OF STRUCTURES FORMED FROM CONCRETE OR MORTAR MIXES HAVING A HYDRAULIC CEMENT BINDING AGENT, WHICH COMPRISES INCORPORATING A GAS-ENTRAINING AGENT AND FLUIDITY-INCREASING AGENT AT ANY STAGE PRIOR TO THE COMPLETION OF THE MIXING OF THE COMPONENTS CONSTITUTING THE MIX, THE FLUIDITY INCREASING AGENT BEING SELECTED FROM THE GROUP CONSISTING OF TARTARIC ACID, CITRIC ACID, SACCHARIC ACID, AND TETRAHYDROXY ADIPIC ACID. 